The benefits of air source heat pumps are similar to ground-source heat systems. Firstly, neither type of system requires the use or storage of external fuel. The systems instead run on electricity, which eliminates the need for a gas connection or storage of oil/solid fuel. Air source heat pumps present an advantage over ground source heat pumps because they require less space to install. Instead of requiring the installation of buried underground coils, air source systems can be fitted using much less space and are therefore, more suited for an urban home.

In the same way that a fridge uses refrigerant to extract heat from the inside, keeping your food cool, an air source heat pump extracts heat from the outside air and uses it to heat your home and hot water. An air-source heat pump has three main parts:

The efficiency of air source systems is measured by a coefficient of performance (CoP). CoPs for air source systems are comparable with ground-source heat pumps, and generally range between 3 and 4.  This means that for every unit of electricity used to power the pump, 3-4 units of heat are produced, making it an efficient way of heating a building.  It is even possible for air source heat pumps to extract useful heat from air at temperatures as low as minus 15ºC.